In industrial facilities, research laboratories and educational environments, chemicals are frequently stored. Many of these chemicals produce, or may produce, gases, if the chemicals form a vapor naturally or if they unexpectedly react with another reagent. If these gases are not released, over pressurization of the container may lead to explosion of the container caused by gas build-up therein. Thus, release of gas build-up in chemical storage vessels is necessary to maintain safe storage of chemical agents.
Conventionally, the pressure in such containers is checked periodically, and the caps thereof loosened to release any pressure. Caps/valves have been previously provided, which allow for release of gas and/or fluids. However, such caps/valves differ from the present invention in various respects.
For example, U.S. Pat. No. 4,640,304 provides an overflow vent valve. Unlike the present invention, the overflow vent valve of the '304 patent is used inside of a pipe, to vent gases there from. To do so, a lightweight ball is employed that floats on the liquid inside the pipeline, which is prevent the liquid from exiting the pipeline. However, if such a valve were employed in a movable apparatus such as a container, it would fail to prevent spillage there from when the container was tilted from the vertical position.
It is an object of the present invention to provide an improved vent cap for containers housing volatile liquids. In particular, it is an object of the present invention to provide a vent cap that allows built up gases within the container to vent, while also automatically sealing the container upon tipping thereof. Such a vent cap will allow gases to be vented while a container is upright, while preventing spillage of liquids there from if the container is tipped from its upright position.
It is a further object of the present invention to provide such a vent cap as described above with a back up venting system so that, if the main venting system becomes inoperable, or if the container is tipped and, simultaneously gas pressure increases to a dangerous level, the gases may be vented. This will allow some spillage of volatile liquids, but avoid the less desirable explosion.